Temps outside were in the 90's over the last 6 weeks here. Well the temperature dropped 25 degrees last night, low humidity now. The car is ice cold at idle today. Gonna take it to the shop next week to have the pressures checked.

I'm not smart on AC systems but I'm guessing they all work on the same principle whether it's in your home or in your dashboard. Is it possible for a car's evaporator to ice up in dense humidity? I had a fridge once that would ice up the evaporator coils to a point where the fan couldn't push air anymore and it was always on super humid days when this would happen. Once I got done throwing out spoiled food and mopping up the floor and the fridge, I'd have to let it sit a few hours and empty the condensation tray underneath a few times and it would behave again for a while. I'm told that a car's AC shouldn't have that kind of cooling capacity but a guy with no common sense would question it anyway.

I got a 2007 crown vic - 4.6L, At idle the a/c blows hot & the compressor cycles frequently. Once you get moving like around 15 mph or more its ice cold. Anybody have any ideas whats wrong??

Quote:

Originally Posted by rtg143

The cycling is like it's low on freon, but they don't get ice cold driving. See what the pressure readings are.

If the radiator cooling fan will not turn on with the A/C on then you will get frequent cycling sitting still and poor A/C. When you start moving, andf get airflow through the condensor, A/C starts working again. See it all the time on PT Cruisers all the time. The low speed fan doesn't come on, the high side pressure skyrockets, and the compressor is shut off. When the high side pressure is so high, you'll notice the engine bog before the compressor is shut off.

WARNING IF EQUIPPED WITH A FIRE SUPPRESSION SYSTEM, THE BACKUP POWER SUPPLY MUST BE DEPLETED BEFORE LIFTING THE VEHICLE.

SEE WORKSHOP MANUAL (WSM), SECTION 419-03 FOR DETAILS.

Verify proper cooling fan operation, and if required, replace the cooling fan with a revised motor and fan assembly. Refer to the appropriate WSM, Section 303-03 for Cooling Fan Motor and Shroud Replacement. If the fan is inoperative, replacing the thermostat will not resolve this issue.

Part # 7W1Z-8C607-B

WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
IMPORTANT : Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.

The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.

AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.